Metal-insulator-metal (MIM) capacitor with deep trench (DT) structure and method in a silicon-on-insulator (SOI)

ABSTRACT

A structure forming a metal-insulator-metal (MIM) trench capacitor is disclosed. The structure comprises a multi-layer substrate having a metal layer and at least one dielectric layer. A trench is etched into the substrate, passing through the metal layer. The trench is lined with a metal material that is in contact with the metal layer, which comprises a first node of a capacitor. A dielectric material lines the metal material in the trench. The trench is filled with a conductor. The dielectric material that lines the metal material separates the conductor from the metal layer and the metal material lining the trench. The conductor comprises a second node of the capacitor.

BACKGROUND

The present disclosure relates to capacitors, and, more particularly, toa metal-insulator-metal capacitor with deep trench structure and methodof forming the structure with silicon-on-insulator technology.

Trench capacitors are widely used in various semiconductor applications.For example, embedded dynamic random access memory (DRAM) technology, inwhich trench capacitors can be used, has played an important role in theemerging system-on-chip (SoC) products. Significant system performancegains have been demonstrated by integrating the embedded DRAM and logicunits on the same chip. Given the enormous success of embedded DRAMtechnology achieved on bulk silicon substrates, integrating embeddedDRAM with silicon-on-insulator (SOI) technology will further boost theperformance of high-end SOI server chips. Substrate resistance, however,can limit both DRAM and deep trench capacitance behavior.

A typical deep trench capacitor comprises a deep trench in asemiconductor substrate (e.g., the semiconductor substrate of either abulk silicon wafer or silicon-on-insulator (SOI) wafer). Typically, adoped region within the substrate adjacent to the trench forms onecapacitor plate (i.e., a buried capacitor plate). A dielectric layerlining the trench forms the capacitor dielectric. Finally, a conductivefill material (e.g., a doped polysilicon) within the trench formsanother capacitor plate. A standard contact can be formed to thecapacitor plate within the trench. However, a number of additionalprocessing steps are required to form the buried capacitor platecontact.

For example, if a bulk silicon wafer is used, then the deep trenchcapacitor must be formed such that it extends through an N-dopeddiffusion connector (e.g., an NWELL) in the silicon substrate. Next, afeature is patterned in the NWELL at the top surface of the siliconsubstrate and a contact is formed to this patterned silicon feature.Similarly, if a silicon-on-insulator (SOI) wafer is used, then the deeptrench capacitor must be formed such that it extends through an N-dopeddiffusion connector (e.g., an NBAND) below the buried oxide (BOX) layer.Next, a patterned doped polysilicon feature is formed that extendsthrough the BOX layer to the NBAND and a contact is formed to thispolysilicon feature.

In either case, due to the requirement of an N-doped diffusionconnector, circuit design flexibility is sacrificed. Furthermore, ineither case photolithographic techniques must be used to pattern afeature to the N-doped diffusion connector. Consequently, the groundrules for these additional processing steps must take into accountoverlay tolerances between the contact structures and the deep trenchcapacitor itself, critical dimension tolerances, the minimum allowabledistance between the buried trench and the boundary of the n-dopeddiffusion connector, etc. Consequently, process windows are small andthe sizes of the various circuits that incorporate such deep trenchcapacitors (e.g., SRAM cells) are not optimized.

SUMMARY

According to one embodiment herein, a structure forming ametal-insulator-metal (MIM) trench capacitor is disclosed. The structurecomprises a multi-layer substrate having a metal layer and at least onedielectric layer. A trench is etched into the substrate, passing throughthe metal layer. The trench is lined with a metal material that is incontact with the metal layer, which comprises a first node of acapacitor. A dielectric material lines the metal material in the trench.The trench is filled with a conductor. The dielectric material thatlines the metal material separates the conductor from the metal layerand the metal material lining the trench. The conductor comprises asecond node of the capacitor.

According to another embodiment herein, a semiconductor structure isdisclosed. The structure comprises a wafer comprising an insulatorlayer, a metal layer below the insulator layer, and a substrate belowthe metal layer. A trench in the wafer extends through the insulatorlayer, through the metal layer, and at least partially into thesubstrate. A metal sidewall lines the trench such that the metalsidewall is in contact with the metal layer. The metal layer comprises afirst node of a capacitor. A dielectric material lines the metalsidewall. A conductive fill material fills the trench such that theconductive fill material is not in contact with the metal layer. Theconductive fill material comprises a second node of the capacitor.

According to another embodiment herein, a method of forming a capacitorstructure is disclosed. The method comprises forming a multi-layersemiconductor substrate comprising a metal layer and at least one otherlayer. A trench is formed in the multi-layer substrate. A metal sidewallis formed within the trench such that the metal sidewall is in contactwith the metal layer. The metal layer is a first node of the capacitorstructure. The metal sidewall is lined with a dielectric material. Thetrench is filled with a conductive fill material such that theconductive fill material in the trench is not in contact with the metallayer. The conductive fill material is a second node of the capacitorstructure.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments herein will be better understood from the followingdetailed description with reference to the drawings, which are notnecessarily drawing to scale and in which:

FIGS. 1-9 are schematic diagrams of a sectional view of semiconductorstructure fabricating a capacitor according to embodiments herein;

FIG. 10 is a flow diagram illustrating embodiments herein;

FIGS. 11-17 are schematic diagrams of a sectional view of semiconductorstructure fabricating a capacitor according to embodiments herein;

FIG. 18 is a flow diagram illustrating embodiments herein;

FIGS. 19-22 are schematic diagrams of a sectional view of semiconductorstructure fabricating a capacitor according to embodiments herein;

FIG. 23 is a flow diagram illustrating embodiments herein;

FIGS. 24-29 are schematic diagrams of a sectional view of semiconductorstructure fabricating a capacitor according to embodiments herein;

FIG. 30 is a flow diagram illustrating embodiments herein;

DETAILED DESCRIPTION

Referring now to the drawings, and more particularly to FIGS. 1-9, thereare shown exemplary illustrations of the method and structures of acapacitor embedded in a deep trench in a semiconductor.

For purposes herein, a “semiconductor” is a material or structure thatmay include an implanted impurity that allows the material to sometimesbe a conductor and sometimes be an insulator, based on electron and holecarrier concentration. As used herein, “implantation processes” can takeany appropriate form (whether now known or developed in the future) andcan comprise, for example, ion implantation, etc.

FIG. 1 illustrates a schematic diagram of a sectional view of amulti-layer substrate 10 for fabricating a metal-insulator-metalcapacitor with deep trench structure.

The multi-layer substrate 10 includes a silicon base layer 13, a metallayer 16 (which may comprise a silicide), a dielectric (or insulator)layer 19, and an SOI layer 22. A sacrificial layer 25, such as an oxidelayer, may cover the SOI layer 22.

For purposes herein, an “insulator” is a relative term that means amaterial or structure that allows substantially less (<95%) electricalcurrent to flow than does a “conductor.” The dielectrics (insulators)mentioned herein can, for example, be formed by plasma deposition ofSiO2 or SiO2 based materials by reacting either tetra-ethyl-ortho-silane(TEOS) or silane with O2 or activated O2, i.e. O3 or O—. Alternatively,the dielectrics herein may be formed from any of the many candidate highdielectric constant (high-k) materials, including but not limited tosilicon nitride, silicon oxynitride, a gate dielectric stack of SiO2 andSi3N4, and metal oxides like tantalum oxide. The thickness ofdielectrics herein may vary contingent upon the required deviceperformance.

The conductors mentioned herein can be formed of any conductivematerial, such as polycrystalline silicon (polysilicon), amorphoussilicon, a combination of amorphous silicon and polysilicon, andpolysilicon-germanium, rendered conductive by the presence of a suitabledopant. Alternatively, the conductors herein may be one or more metals,such as tungsten, hafnium, tantalum, molybdenum, titanium, nickel,aluminum, or copper, or a metal silicide, any alloys of such metals, andmay be deposited using physical vapor deposition, chemical vapordeposition, or any other technique known in the art.

As shown in FIG. 2, a deep trench 28 is formed in the multi-layersubstrate 10. The trench 28 passes through the sacrificial layer 25, theSOI layer 22, the dielectric layer 19, the metal layer 16, and at leastpartially into the silicon base layer 13. The trench 28 can be formed byany appropriate means, such as by applying a pattern and etching thevarious layer materials.

FIG. 3 shows a metal sidewall 31 formed in the trench 28. The metalsidewall 31 connects to the metal layer 16. In some embodiments, themetal sidewall 31 may connect only to the bottom surface of the metallayer 16. The metal sidewall 31 can be any appropriate conductivematerial, such as silicide and may be the same material or differentmaterial as the metal layer 16. The metal layer 16 forms a first node ofa capacitor structure.

After the metal sidewall 31 is formed, a dielectric material 34 isdeposited in the trench 28, as shown in FIG. 4.

In FIG. 5, a conductor 37 is formed in the trench 28 by filling with aconductive fill material and recessing the conductor 37 to anappropriate height within the trench 28. In some embodiments, theconductor 37 can be connected to the SOI layer 22. The trench is filledwith a conductive fill material such that the conductive fill materialin the trench is not in contact with the metal layer 16. The dielectricmaterial 34 separates the conductor 37 from the metal layer 16 and themetal sidewall 31 lining the trench 28. Recessing of the conductive fillmaterial can be accomplished by any appropriate means known in the art.The conductive fill material may be the same material or differentmaterial as the metal layer 16 and the same as or different than thematerial used for the metal sidewall 31. The conductor 37 forms a secondnode of the capacitor structure.

In FIG. 6, the dielectric material 34 is removed from the exposed areasof the trench 28. Then, as shown in FIG. 7, a poly cap 40 is depositedon the conductor 37. The poly cap 40 is recessed by any appropriatemeans known in the art to enable the metal sidewall to be removed fromthe SOI layer 22, if desired. Otherwise, the trench 28 is filled withpoly and recessed to shorten the trench height to the SOI layer 22, asshown in FIG. 8.

FIG. 9 shows, after forming the deep trench MIM capacitor, processing ofthe multi-layer substrate 10 can proceed to STI patterning and etchingas is known in the art.

When patterning any material herein, the material to be patterned can begrown or deposited in any known manner and a patterning layer (such asan organic photoresist or hardmask) can be formed over the material. Thepatterning layer (resist) can be exposed to some pattern of lightradiation (e.g., patterned exposure, laser exposure, etc.) provided in alight exposure pattern, and then the resist is developed using achemical agent. This process changes the physical characteristics of theportion of the resist that was exposed to the light. Then one portion ofthe resist can be rinsed off, leaving the other portion of the resist toprotect the material to be patterned. A material removal process is thenperformed (e.g., plasma etching, etc.) to remove the unprotectedportions of the material to be patterned. The resist is subsequentlyremoved to leave the underlying material patterned according to thelight exposure pattern.

A hardmask can be formed of any suitable material, whether now known ordeveloped in the future, such as a metal or organic or inorganic (Si3N4,SiC, SiO2C (diamond)) hardmask, that has a hardness greater than thesubstrate and insulator materials used in the remainder of thestructure.

FIG. 10 shows a logic flowchart for an embodiment for a method offabricating a capacitor in a semiconductor including providing an SOIwafer including a plurality of layers 100. A trench is formed in thewafer, at 103. At 106, sidewalls are formed within the trench such thatthe metal sidewall is in contact with the metal layer. The sidewalls maybe a metal or silicide material. The metal sidewall is lined with adielectric material, at 109. The trench is filled with a conductive fillmaterial 112 such that the conductive fill material in the trench is notin contact with the metal layer and the conductive fill is recessed 115.At 118, the dielectric is removed from exposed areas. At 121, theconductive fill is capped with a poly cap. The exposed metal sidewallcan be optionally removed, at 124. At 127, the trench is filled withpoly and recessed to the SOI layer, at 130. At 133, STI processing canproceed with etching, as is known in the art.

In another embodiment, a silicon layer is bonded to an insulator layerafter formation of the deep trench MIM capacitor. FIG. 11 illustrates aschematic diagram of a sectional view of a multi-layer substrate 10 forfabricating a metal-insulator-metal capacitor with deep trench structureaccording to this embodiment. The multi-layer substrate 10 includes asilicon base layer 13, a metal layer 16 (which may comprise a silicide),and a dielectric (or insulator) layer 19.

As shown in FIG. 12, a deep trench 28 is formed in the multi-layersubstrate 10. The trench 28 passes through the dielectric layer 19, themetal layer 16, and at least partially into the silicon base layer 13.The trench 28 can be formed by any appropriate means, such as byapplying a pattern and etching the various layer materials.

FIG. 13 shows a metal sidewall 31 formed in the trench 28. The metalsidewall 31 connects to the metal layer 16. In some embodiments, themetal sidewall 31 may connect only to the bottom surface of the metallayer 16. The metal sidewall 31 can be any appropriate conductivematerial, such as silicide. The metal layer 16 forms a first node of acapacitor structure.

After the metal sidewall 31 is formed, a dielectric material 34 isdeposited in the trench 28, as shown in FIG. 14.

In FIG. 15, a conductor 37 is formed in the trench 28 by filling with aconductive fill material and recessing the conductor 37 to anappropriate height within the trench 28. Recessing of the conductivefill material can be accomplished by any appropriate means known in theart. The conductor 37 forms a second node of the capacitor structure.

In FIG. 16, a poly cap 40 is deposited on the conductor 37, and anotherdielectric layer 45 is deposited onto the multi-layer substrate 10 ontop of dielectric layer 19.

After dielectric layer 45 is deposited, a silicon layer 48 is bonded tothe dielectric layer 45, as shown in FIG. 17. Processing of themulti-layer substrate 10 can proceed to STI patterning and etching, asis known in the art.

FIG. 18 shows a logic flowchart for an embodiment for a method offabricating a capacitor in a semiconductor including providing asemiconductor substrate having a plurality of layers 141. A trench isformed in the wafer, at 144. At 147, sidewalls are formed within thetrench such that the metal sidewall is in contact with the metal layer.The sidewalls may be a metal or silicide material. The metal sidewall islined with a dielectric material, at 150. The trench is filled with aconductive fill material 153 such that the conductive fill material inthe trench is not in contact with the metal layer and the conductivefill is recessed 156. At 159, the conductive fill is capped with a polycap. At 162, an additional dielectric layer is deposited on thesemiconductor substrate. A silicon layer is bonded to the dielectriclayer, at 165. At 168, STI processing can proceed with etching as isknown in the art.

FIGS. 19-22 show another embodiment of a deep trench MIM capacitor. FIG.19 illustrates a schematic diagram of a sectional view of a multi-layersubstrate 50 for fabricating a metal-insulator-metal capacitor with deeptrench structure according to this embodiment. The multi-layer substrate50 includes a silicon base layer 53, a first dielectric layer 56, ametal layer 59, a second dielectric layer 62, and an SOI layer 65. Asacrificial layer 68, such as an oxide layer, may cover the SOI layer65.

As shown in FIG. 20, a trench 71 is formed in the multi-layer substrate50. The trench 71 passes through the sacrificial layer 68, the SOI layer65, the second dielectric layer 62, the metal layer 59, and at leastpartially into the first dielectric layer 56. The trench 71 can beformed by any appropriate means, such as by applying a pattern andetching the various layer materials.

FIG. 21 shows a metal sidewall 74 formed in the trench 71. The metalsidewall 74 connects to the metal layer 59. The metal sidewall 74 can beany appropriate conductive material, such as silicide and may be thesame material or different material as the metal layer 59. The metallayer 59 forms a first node of a capacitor structure. After the metalsidewall 74 is formed, a dielectric material 77 is deposited in thetrench 71. A conductor 81 is formed in the trench 71 by filling with aconductive fill material and recessing the conductor 81 to anappropriate height within the trench 71. The dielectric material 77separates the conductor 81 from the metal layer 59 and the metalsidewall 74 lining the trench 71. Recessing of the conductive fillmaterial can be accomplished by any appropriate means known in the art.The conductive fill material may be the same material or differentmaterial as the metal layer 59 and the same as or different than thematerial used for the metal sidewall 74. The conductor 81 forms a secondnode of the capacitor structure.

In FIG. 22, insulating spacers 84, 85 are formed on the conductor 81.Then the trench 71 is filled with poly forming a poly cap 87 andrecessed to an appropriate level. Processing of the multi-layersubstrate 50 can proceed to STI patterning and etching, as is known inthe art.

FIG. 23 shows a logic flowchart for an embodiment for a method offabricating a capacitor in a semiconductor including providing asemiconductor substrate having a plurality of layers 172. A trench isformed in the wafer, at 175. At 178, sidewalls are formed within thetrench such that the metal sidewall is in contact with the metal layer.The sidewalls may be a metal or silicide material. The metal sidewall islined with a dielectric material, at 181. The trench is filled with aconductive fill material 184 such that the conductive fill material inthe trench is not in contact with the metal layer and the conductivefill is recessed 187. At 190, insulating spacers are formed on theconductive fill. At 193, the trench is filled with poly and recessed tothe SOI layer, at 196. At 199, STI processing can proceed with etching,as is known in the art.

FIGS. 24-29 show another embodiment of a deep trench MIM capacitor inwhich a silicon layer is bonded to an insulator layer after formation ofthe deep trench MIM capacitor. FIG. 24 illustrates a schematic diagramof a sectional view of a multi-layer substrate 50 for fabricating ametal-insulator-metal capacitor with deep trench structure according tothis embodiment. The multi-layer substrate 50 includes a silicon baselayer 53, a first dielectric layer 56, a metal layer 59, and a seconddielectric layer 62.

As shown in FIG. 25, a trench 71 is formed in the multi-layer substrate50. The trench 71 passes through the second dielectric layer 62, themetal layer 59, and at least partially into the first dielectric layer56. The trench 71 can be formed by any appropriate means, such as byapplying a pattern and etching the various layer materials.

FIG. 26 shows a metal sidewall 74 formed in the trench 71. The metalsidewall 74 connects to the metal layer 59. The metal sidewall 74 can beany appropriate conductive material, such as silicide and may be thesame material or different material as the metal layer 59. The metallayer 59 forms a first node of a capacitor structure. After the metalsidewall 74 is formed, a dielectric material 77 is deposited in thetrench 71. A conductor 81 is formed in the trench 71 by filling with aconductive fill material. Any excess material is removed. The dielectricmaterial 77 separates the conductor 81 from the metal layer 59 and themetal sidewall 74 lining the trench 71. The conductive fill material maybe the same material or different material as the metal layer 59 and thesame as or different than the material used for the metal sidewall 74.The conductor 81 forms a second node of the capacitor structure.

In FIG. 27, the conductor 81 is recessed and a poly cap 87 is depositedon the conductor 81. Any excess poly material is removed.

In FIG. 28, the second dielectric layer 62 is recessed. The portion ofthe metal sidewall 74 above the metal layer 59 is also recessed.Recessing of the materials can be accomplished by any appropriate meansknown in the art.

In FIG. 29, another dielectric layer 90 is deposited onto themulti-layer substrate 50 on top of the metal layer 59. After dielectriclayer 90 is deposited, a silicon layer 93 is bonded to the dielectriclayer 90. Processing of the multi-layer substrate 50 can proceed to STIpatterning and etching, as is known in the art.

FIG. 30 shows a logic flowchart for an embodiment for a method offabricating a capacitor in a semiconductor including providing asemiconductor substrate having a plurality of layers 203. A trench isformed in the wafer, at 206. At 209, sidewalls are formed within thetrench such that the metal sidewall is in contact with the metal layer.The sidewalls may be a metal or silicide material. The metal sidewall islined with a dielectric material, at 212. The trench is filled with aconductive fill material 215 such that the conductive fill material inthe trench is not in contact with the metal layer. Excess material isremoved, at 218. The conductive fill is recessed, at 221. At 224, theconductive fill is capped with a poly cap, and excess poly material isremoved, at 227. At 230, the dielectric layer and exposed sidewall isrecessed. At 233, an additional dielectric layer is deposited on thesemiconductor substrate. A silicon layer is bonded to the dielectriclayer, at 236. At 239, STI processing can proceed with etching, as isknown in the art.

In Summary, according to one embodiment herein, a structure forming ametal-insulator-metal (MIM) trench capacitor is disclosed. The structurecomprises a multi-layer substrate having a metal layer and at least onedielectric layer. A trench is etched into the substrate, passing throughthe metal layer. The trench is lined with a metal material that is incontact with the metal layer, which comprises a first node of acapacitor. A dielectric material lines the metal material in the trench.The trench is filled with a conductor. The dielectric material thatlines the metal material separates the conductor from the metal layerand the metal material lining the trench. The conductor comprises asecond node of the capacitor.

According to another embodiment herein, a semiconductor structure isdisclosed. The structure comprises a wafer comprising an insulatorlayer, a metal layer below the insulator layer, and a substrate belowthe metal layer. A trench in the wafer extends through the insulatorlayer, through the metal layer, and at least partially into thesubstrate. A metal sidewall lines the trench such that the metalsidewall is in contact with the metal layer. The metal layer comprises afirst node of a capacitor. A dielectric material lines the metalsidewall. A conductive fill material fills the trench such that theconductive fill material is not in contact with the metal layer. Theconductive fill material comprises a second node of the capacitor.

According to another embodiment herein, a method of forming a capacitorstructure is disclosed. The method comprises forming a multi-layersemiconductor substrate comprising a metal layer and at least one otherlayer. Forming a trench in the multi-layer substrate. Forming a metalsidewall within the trench such that the metal sidewall is in contactwith the metal layer. The metal layer is a first node of the capacitorstructure. Lining the metal sidewall with a dielectric material. Fillingthe trench with a conductive fill material such that the conductive fillmaterial in the trench is not in contact with the metal layer. Theconductive fill material is a second node of the capacitor structure.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments herein. In this regard, each block in the flowchart or blockdiagrams may represent a module, segment, or portion of code, whichcomprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that, in somealternative implementations, the functions noted in the block mightoccur out of the order noted in the figures. For example, two blocksshown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The method as described above is used in the fabrication of integratedcircuit chips. The resulting integrated circuit chips can be distributedby the fabricator in raw wafer form (that is, as a single wafer that hasmultiple unpackaged chips), as a bare die, or in a packaged form. In thelatter case the chip is mounted in a single chip package (such as aplastic carrier, with leads that are affixed to a motherboard or otherhigher level carrier) or in a multichip package (such as a ceramiccarrier that has either or both surface interconnections or buriedinterconnections). In any case, the chip is then integrated with otherchips, discrete circuit elements, and/or other signal processing devicesas part of either (a) an intermediate product, such as a motherboard, or(b) an end product. The end product can be any product that includesintegrated circuit chips, ranging from toys and other low-endapplications to advanced computer products having a display, a keyboardor other input device, and a central processor.

For purposes herein, “sidewall spacers” are structures that arewell-known to those ordinarily skilled in the art and are generallyformed by depositing or growing a conformal insulating layer (such asany of the insulators mentioned above) and then performing a directionaletching process (anisotropic) that etches material from horizontalsurfaces at a greater rate than its removes material from verticalsurfaces, thereby leaving insulating material along the verticalsidewalls of structures. This material left on the vertical sidewalls isreferred to as sidewall spacers.

In addition, terms such as “right”, “left”, “vertical”, “horizontal”,“top”, “bottom”, “upper”, “lower”, “under”, “below”, “underlying”,“over”, “overlying”, “parallel”, “perpendicular”, etc., used herein areunderstood to be relative locations as they are oriented and illustratedin the drawings (unless otherwise indicated). Terms such as “touching”,“on”, “in direct contact”, “abutting”, “directly adjacent to”, etc.,mean that at least one element physically contacts another element(without other elements separating the described elements).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of this disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescriptions of the various embodiments of the present invention havebeen presented for purposes of illustration, but are not intended to beexhaustive or limited to the embodiments disclosed. Many modificationsand variations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

What is claimed is:
 1. A method of forming a capacitor structure, saidmethod comprising: forming a substrate comprising: a metal layer; and atleast one other layer; forming a trench in said substrate; forming ametal sidewall within said trench such that said metal sidewall is incontact with said metal layer, said metal layer comprising a first nodeof said capacitor structure; lining said metal sidewall with adielectric material; and filling said trench with a conductive fillmaterial such that said conductive fill material in said trench is notin contact with said metal layer, said conductive fill materialcomprising a second node of said capacitor structure, said substratecomprising a dielectric layer above said metal layer, said methodfurther comprising: after said filling said trench with conductive fillmaterial, recessing said conductive fill material in said trench;capping said conductive fill material; recessing said dielectric layerand said metal sidewall above said metal layer; and depositing anotherdielectric layer on said metal layer over said conductive fill materialand said cap.
 2. The method of claim 1, said forming a substrate furthercomprising: providing a first silicon layer; depositing said metal layeron said first silicon layer; and depositing a dielectric layer on saidmetal layer.
 3. The method of claim 2, said forming a substrate furthercomprising: bonding a Silicon-on-insulator (SOI) layer on saiddielectric layer.
 4. The method of claim 3, further comprising: aftersaid filling said trench with conductive fill material, recessing saidconductive fill material in said trench so as to expose at least anupper section of said trench; removing said metal sidewall from saidupper section of said trench; depositing additional conductive fillmaterial such that said conductive fill material is in contact with saidSOI layer; and capping said conductive fill material.
 5. The method ofclaim 1, said substrate further comprising at least one of: a siliconlayer; a semiconductor; and a conductor layer.
 6. The method of claim 1,further comprising: after said filling said trench with conductive fillmaterial, recessing said conductive fill material in said trench so asto expose at least an upper section of said trench; and capping saidconductive fill material.
 7. The method of claim 1, further comprisingforming a first contact to said metal layer and a second contact to saidconductive fill material.
 8. The method of claim 1, further comprising:bonding a Silicon-on-insulator layer on said another dielectric layer.9. A method of forming a capacitor structure, said method comprising:forming a substrate comprising: a metal layer; and at least one otherlayer; forming a trench in said substrate; forming a metal sidewallwithin said trench such that said metal sidewall is in contact with saidmetal layer, said metal layer comprising a first node of said capacitorstructure; lining said metal sidewall with a dielectric material; andfilling said trench with a conductive fill material such that saidconductive fill material in said trench is not in contact with saidmetal layer, said conductive fill material comprising a second node ofsaid capacitor structure, said substrate comprising a dielectric layerabove said metal layer, said method further comprising: after saidfilling said trench with conductive fill material, recessing saidconductive fill material in said trench; capping said conductive fillmaterial; recessing said dielectric layer and said metal sidewall abovesaid metal layer; depositing another dielectric layer on said metallayer over said conductive fill material and said cap; and bonding aSilicon-on-insulator layer (SOI) on said another dielectric layer. 10.The method of claim 9, said forming a substrate further comprising:providing a first silicon layer; depositing said metal layer on saidfirst silicon layer; and depositing said dielectric layer on said metallayer.
 11. The method of claim 9, said substrate further comprising atleast one of: a silicon layer; a semiconductor; and a conductor layer.12. The method of claim 9, said recessing said conductive fill materialin said trench further comprising: expose exposing at least an uppersection of said trench.
 13. The method of claim 9, further comprisingforming a first contact to said metal layer and a second contact to saidconductive fill material.
 14. A method comprising: forming a substratecomprising: providing a first silicon layer, depositing a metal layer onsaid first silicon layer, depositing a dielectric layer on said metallayer, and bonding a Silicon-on-insulator (SOI) layer on said dielectriclayer; forming a trench in said substrate through said metal layer, saiddielectric layer, and said SOI layer; forming a metal sidewall withinsaid trench such that said metal sidewall is in contact with said metallayer, said metal layer comprising a first node of a capacitorstructure; lining said metal sidewall with a dielectric material;filling said trench with a conductive fill material such that saidconductive fill material in said trench is not in contact with saidmetal layer, said conductive fill material comprising a second node ofsaid capacitor structure; after said filling said trench with conductivefill material, recessing said conductive fill material in said trench soas to expose at least an upper section of said trench; removing saidmetal sidewall from said upper section of said trench; depositingadditional conductive fill material such that said conductive fillmaterial is in contact with said SOI layer; and capping said conductivefill material.